452 A BRIEF SURVEY OF HUMAN HISTORY

become popular and useful-—pumps, ship-logs, power-looms
and many others, and, from the flight of birds, designed a
flying machine which in his hands remained a sketch. The
same brain worked, too, in studying the anatomy of animals,
the traces and meaning of fossils, the laws of motion and

their relation to sound and ligjit.....The practical work,

on which he chiefly lived, was that needed by the rulers
and people of his day—great hydraulic and irrigation works
in Lombardy, fortifications for Duke Ludovico Sfroza of
Milan ... Besides his engineering achievements in fortifi-
cation, he is credited with the invention of a submarine boat
and a breech-loading cannon. Such intermixture of construc-
tive work with the planned destruction of human life has
gone on so far throughout the course of history.'

The above sketch of Leonardo da Vinci correctly depicts
the entire range and character of technology in the Modern
World. What we witness in the world to-day is but the
logical development of the Italian's anticipations. To know
more about these developments one has to go to special
histories on the subject, like The Endless Quest by F. W.
Westaway. In addition to the inventions of the Chinese
.(mariner's compass, gun-powder, paper and the printing-
press), and the textile and locomotive engines, referred to
earlier, we might mention only a few more scientific achieve-
ments here to illustrate the above remarks. The operation
of all kinds of machinery for all varieties of purposes be-
came easy on account of the discovery, first of steam-power,
and then of electricity. The American Franklin, the Italian
Volta, and the British Faraday, by their investigations re-
garding electrical phenomena made the telegraph possible
in 1835. The first under-sea cable was laid between England
and France in 1851. The discovery of the ' Hertzian Waves,'
or electric vibrations in ether, introduced the wireless with